Optically active 4-halo-3-hydroxybutyric acid esters are important intermediates for the synthesis of various medicinal compounds, optically active biologically active substances and derivatives thereof.
For the production of an optically active 4-halo-3-hydroxybutyric acid ester, there is known an asymmetric enzymatic reduction (J. Am. Chem. Soc., 105, 5925 (1988); Ann. N.Y. Acad. Sci., 613, 628 (1990); Japanese Patent Application Laid-open No. 277494/1989; etc.), as well as an asymmetric reduction with the aid of a microorganism (Japanese Patent Application Laid-open No. 146191/1986, etc.) and an asymmetric reduction with the aid of Lactobacillus fermentum and Lactobacillus kelfa (Biocatalysis, Vol. 5, pp. 325 to 332 (1992)).
The enzymatic asymmetric reduction process, however, is disadvantageous in that the process is complicated and can not be carried out with simplicity. The asymmetric reduction processes with the aid of a microorganism are also disadvantageous in that the practically sufficient efficiency of the processes and the optical purity of the product optically active compound can not be obtained and that the microorganisms usable in the reactions are extremely restricted.
Under the circumstances, the establishment of an economical and expedient process for production of an optically active 4-halo-3-hydroxybutyric acid ester of high optical purity has been demanded.